Microtubules are dynamic constituents of the cytoplasm of all eukaryotic cells. Perturbation of the intracellular state of microtubules interferes with basic cell functions. Recent investigations have included the application of the technologies of recombinant DNA and monoclonal antibodies to the study of microtubule proteins and the introduction of new experimental approaches to the study of microtubule assembly and function. As these investigations proceed, our understanding of the complexity and regulation of microtubules and the cytoskeleton has increased in sophistication. The new directions in microtubule research have diverged sufficiently that the time is appropriate for an intensive conference to help to refocus and redefine central questions about microtubules and to improve communications between investigators working on similar problems but from different points of view. We plan to hold a conference in New York City from December 3-6, 1984, on "Dynamic Aspects of Microtubule Biology," sponsored by the New York Academy of Sciences. Topics to be considered include factors regulating pools of microtubule assembly in vivo, as well as in cell-free systems, experimental interference with microtubule dynamics and aspects of microtubule function. Most active investigators in these areas have already indicated their enthusiasm for participating in such a conference. The format of the conference is designed to encourage interaction between participants through both formal and informal discussion, as well as through the presentation of lectures and posters. The proceedings, to be published as a monograph in the Annals of the New York Academy of Sciences, should serve to present a compilation of the most current research in the field as of December, 1984.